This project investigates the role of luteinizing hormone releasing hormone and estrogens in the synthesis and release of gonadotropins in a small animal pituitary model in which the pituitary has been permanently separated from the hypothalamus. The separation from the hypothalamus is carried out by stalk section following which a metal barrier is implanted between the cut ends of the infundibular stem. Initial investigations have indicated that such an isolated pituitary is responsive to synthetic LHRH, and that the luteinizing hormone response to LHRH stimulation is enhanced by the administration of estradiol. Currenty, the timing and dosage of LHRG and estrogen administration are being investigated, the object being to determine optimal responses. Response in the female rat are being compared to those in the male animal. Simultaneously we are investigating the role of LHRH in gonadotropin synthesis, both in vivo (in the small animal model), in vitro using recently removed segments of anterior pituitary glands and cultures of cells derived from the anterior pituitary. BIBLIOGRAPHIC REFERENCE: Greeley, G.H. Jr., Allen, M.B., Jr. and Mahesh V.B.: Potentiation of luteinizing hormone release by estradiol at the level of te pituitary. Neuroendocrinol. 18:233-241, 1975.